Growth and decline of arboreal fungi that prey on Bursaphelenchus xylophilus and their predation rate

Pine wilt disease caused by pine wood nema-todes is a deadly disease of the genus Pinus requiring strong quarantine measures.Since its discovery,it has been widely distributed throughout the world.China is one of the coun-tries with a severe rate of infections due to its abundant pine resources.In this study,nematode-trapping fungi were collected from pine trees in Ninghai City,Zhejiang Prov-ince,which is the key area of pine wilt control in Febru-ary,May,September,October and November.The results showed that nematode-trapping fungi of pine are abundant,especially the number and species detected in each month and are quite different;species of fungi in July,Septem-ber and November were more numerous and had higher separation rates.The dominant species in November was Arthrobotrys oligospora followed by Arthrobotrys cladodes;July and September it was A.cladodes.In each part of the tree,A.cladodes was the most widely distributed with a high separation rate.Therefore,it is the dominant fungal species in the area.Arboreal Bursaphelenchus xylophilus-trapping fungi are dependent on pine wood nematodes,and none were isolated from healthy pine trees.More arboreal B.xylophilus-trapping fungi were found under the bark than in the xylem.There is a close relationship between arboreal B.xylophilus-trapping fungi and pine wood nematodes.How to make use of these resources to reduce the damage of pine wood nematode fusarium is the focus of future research.

Experimental clearance rate and intraguild predation of jellyfish Cyanea nozakii

Cyanea nozakii,a common jellyfish distributed in offshore China,has a complex trophic relationship with other zooplankton groups.However,few studies have reported the predation rates and prey selection patterns of C.nozakii medusae on different prey items.Research is also lacking on the intraguild predation of Aurelia coerulea(another common bloom jellyfish in offshore China)by C.nozakii.To address the knowledge gaps,the clearance rates of C.nozakii for different prey items,including copepods(small<1000μm and large>1000μm),fish larvae,and gelatinous prey(hydromedusae,A.coerulea ephyrae,and chaetognaths),were measured.The influence of predator size on the clearance rate was also determined.Additionally,we examined the intraguild predation of C.nozakii on A.coerulea medusae.The clearance rates of C.nozakii varied widely with prey organisms,being independent of prey concentrations.Gelatinous organisms,except for chaetognaths,were captured with considerably high efficiency,followed by fish larvae and copepods,indicating the preferential prey selection of gelatinous organisms by C.nozakii.The clearance rate increased linearly with the cross-sectional area of C.nozakii.Body size in medusae may,to some extents,underpin their capacity to capture more prey by increasing the encounter rate and capture success through ontogeny.C.nozakii preyed voraciously on A.coerulea in high feeding efficiency,but the clearance rate decreased with increasing A.coerulea(as prey)size.This phenomenon of intraguild predation suggests a speculative hypothesis of potential population regulation of A.coerulea by C.nozakii.The information regarding the feeding ecology of C.nozakii reported in this study is important for understanding plankton dynamics in marine ecosystems with extensive occurrences of this jellyfish.

Natural predators of polyps of three scyphozoans:Nemopilema nomurai,Aurelia coerulea,and Rhopilema esculentum

Jellyfish blooms have become a hot research topic in recent decades because they pose a serious threat to fisheries,coastal industries,tourism,and the marine ecosystem.The life cycle of scyphozoan jellyfish consists of a pelagic medusa stage and a benthic polyp stage,where asexual reproduction and strobilation of the polyps directly affect the abundance of ephyra and subsequently medusa abundance.The dynamics of polyps are affected by both environmental and biological factors,and predation by natural predators is one of the most important biological factors.Nemopilema nomurai,Aurelia coerulea,and Rhopilema esculentum are three scyphozoan species that are commonly found in Chinese coastal waters,and previous studies reported that the survivorship of polyps differs among the three species when they are exposed to the same benthic community.To identify potential natural predators of polyps of these three species in Chinese coastal waters and to determine whether the predation rates on polyps of the three species differ,we collected 39 species of macrozoobenthos from the Bohai Sea,Yellow Sea,and East China Sea from May 2014 to June 2016 and conducted predation tests and predation rate measurements.We found that the nudibranchs Pleurobranchaea novaezealandiae,Okenia plana,and Chromodoris tinctoria and the sea anemones Paracalliactis sinica,Calliactis japonica,Anthopleura incerta,and Anthopleura midori could prey on the polyps of all three scyphozoan species.The predation rates increased with the body length of the predators.The predations rates were also related to the polyp species,although the different predators showed no consistent preference for a particular species of polyp.Our results indicate that introducing predators to locations inhabited by polyps might be a way to control the benthic polyp populations and prevent subsequent jellyfish blooms.

Breeding ecology of two sympatric laughingthrushes(Trochalopteron milnei and Garrulax berthemyi)in southwestern China

Here we documented up-to-date information on breeding ecology of Buffy Laughingthrush(Garrulax berthemyi),an endemic species of China,and a sympatric coordinal Red-tailed Laughingthrush(Trochalopteron milnei),in southwestern China.Furthermore,we compared breeding ecology of these two sympatric species.No significant differences were found in clutch size,egg size,nest size,nest height,nest habitat and predation rate between these two species except nests depth,nests cover and eggs color.The Red-tailed Laughingthrush nestlings differed from those of the Buffy Laughingthrush in gape morphology and the extent of down.Observation of breeding behavior showed that cooperative breeding might exist in the population of Buffy Laughingthrush.

Assessment of predatory ability of native and non-native freshwater gammaridean species： A rapid test with water fleas as prey

Predation rate with relation to species, sex and water temperature was tested among four different gammaridean spe- cies： Dikerogammarus villosus, Gammarus roeselii, Gammarus pulex and Gammarus fossarum. Tests were performed in micro- cosms in climate-controlled rooms at five different temperatures. Daphnia magna, a common water flea, served as prey. On ave- rage D. villosus showed the highest consumption rate of Daphnia magna over the entire temperature range, followed in decreas- ing order by G pulex, G roeselii and G fossarum. The predation rate of all species showed a distinct peak at 20~C. Correction of predation rates for body size gave somewhat different results. D. villosus is then still the most predatory of all gammaridean spe- cies tested followed by G. pulex, G. fossarum and G roeselii. The outcome of the Daphnia tests is consistent with results of other studies with different prey. This supports that the Daphnia test is a good and quick indicator of the predatory abilities in gam- maridean species at varying temperatures, and allows the prediction of how changing temperature regimes influence invasion impacts